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Effect of different catalysts on urea–formaldehyde resin synthesis
Author(s) -
Sun QiNing,
Hse ChungYun,
Shupe Todd F.
Publication year - 2014
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.40644
Subject(s) - prepolymer , condensation polymer , urea formaldehyde , catalysis , ether , methylene , polymer chemistry , formaldehyde , melamine , polymerization , urea , polymer , melamine resin , materials science , chemistry , organic chemistry , polyurethane , adhesive , coating , layer (electronics)
Four catalysts (H 2 SO 4 , HCl, H 3 PO 4 , and NaOH/NH 4 OH) were studied in the preparation of melamine modified urea–formaldehyde (UFM) resins. 13 C‐nuclear magnetic resonance spectroscopic analysis of the UFM resins at different synthesis stages revealed the polymer structure and detailed reaction mechanism. Three acidic catalysts (H 2 SO 4 , HCl, and H 3 PO 4 ) enhanced the resin polymerization through the formation of various contents of methylene, ether linkages, and urons. H 3 PO 4 yielded the most terminal ether linkages at the first stage and enhanced polycondensation by depleting all free urea and glycols to form the most linear methylene linkages NHCH 2 NH in the end. However, at the initial synthesis stage, NaOH/NH 4 OH catalyzed the formation of UFM prepolymer to a limited extent with a large amount of free urea left, and therefore produced the final polymer with relatively more substituted methylolureas and linear ether linkages. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40644.